Crushable polyermic rail extension, systems, and methods of making and using the same

ABSTRACT

A rail extension system ( 16 ), comprising: a vehicle rail ( 60 ); a bumper beam ( 20 ); a polymeric rail extension ( 1 ) comprising: a base ( 2 ) extending from one end of the rail extension having vehicle attachment configured to attach to the vehicle rail ( 60 ); a front member  4 ) configured for attachment to the bumper beam ( 20 ); a body ( 5 ) extending from the base ( 2 ) to the front member ( 4 ); an aperture ( 100 ) extending from the base ( 2 ) to the front member ( 4 ); a connection member ( 102 ) attached to the bumper beam ( 20 ) and extending through the aperture ( 100 ) to attach to the vehicle rail ( 60 ).

BACKGROUND

Bumper systems generally extend widthwise, or transversely, across thefront and rear of a vehicle and are mounted to rails that extend in alengthwise direction. Many bumper assemblies for an automotive vehicleinclude a bumper beam and an injection molded energy absorber secured tothe bumper beam with a fascia covering the energy absorber. The systemincluding one or more members that connect the bumper beam to thevehicle chassis/frame is called the rail extension system. Beneficialenergy absorbing bumper systems achieve high efficiency by building loadquickly to just under the load limit of the rails and maintain that loadconstant until the impact energy has been dissipated. There is always aneed to develop low cost, lightweight, and high performance energyabsorbing systems that will deform and absorb impact energy to ensure agood vehicle safety rating and reduce vehicle damage in low speedcollisions. Different components due to their inherent geometry andassembly requirements need different energy absorber designs to satisfythe impact criteria. Therefore, the automotive industry is continuallyseeking economic solutions to improve the overall safety rating of avehicle. Hence, there is a continual need to provide a solution thatwould reduce vehicle damage and/or enhance a vehicle safety rating.

One such component can be a rail extension, which attaches the bumpersystem to the rails. An important aspect to be considered for a railextension is the energy absorbed within the space available between therail and bumper system. Depending upon the space available for a railextension, the size and performance of the rail extension can vary. Forexample, a small space with a short rail extension can result ininadequate energy absorption. In addition, a large space with a longrail extension can result in unstable buckling instead of progressivecrushing, which can lead to low energy absorption.

Polymeric rail extensions can suffer from a reduction in performance dueto high temperatures. In addition, polymeric rail extensions can bedamaged during a towing operation. Furthermore, polymeric railextensions are limited in the materials that are available forelectrophoretic deposition (e.g., e-coating). For example, onlyconductive polymeric materials are available for the e-coating process.In addition, for high speed crashes, polymeric rail extensions may notabsorb similar energy levels as a metal rail extension. Rail extensionscan also be limited by the method of manufacture. For example, injectionmolding of long part lengths prevents the inclusion of a generous draftangle. In addition, tool ejection becomes a challenge when usinginjection molding. Thus, it is difficult to provide structurallysuitable reinforcements in specific areas within the rail extension whenusing injection molding techniques. As such, a need exists for a railextension system that can perform at high temperatures and during towingoperations. In addition, a need exists for a rail extension system thatis not limited by material constraints. Finally, a need exists for arail extension and a method of manufacture that can reduce the toolingcosts and core length while allowing for the inclusion of crushinitiators and reinforcing.

Vehicle rail extensions can slip against the bumper beam due toinadequate engagement resulting in an inefficient absorption of energy.In addition, bumper beams with a “B-shaped” cross section can clash onimpact, resulting in the upper portion and lower portion crushingimproperly and reducing impact absorption. As such, a need exists for arail extension system that can reduce the unstable buckling and slippageof the rail extension and prevent clashing in order to increase theoverall energy absorption of the system.

BRIEF DESCRIPTION

Disclosed, in various embodiments, are rail extensions, rail extensionsystems, and methods for making and using the same.

A rail extension includes: a base extending from one end of the railextension, wherein the base includes vehicle rail attachments configuredto attach to a vehicle rail; a front member configured for attachment toa bumper beam; a body extending from the base and toward the frontmember, wherein the base comprises cells formed by cell walls extendingalong at least a portion of a length of the body from the base towardthe front member and forming cavities therethrough; open channels formedon each side of the body, wherein the open channels are defined by wallsof adjacent cells; wherein the front member comprises a plurality ofbeam attachments that extend from the front member towards the base; andbeam attachment inserts located within the beam attachments.

A rail extension system, includes: a vehicle rail; a bumper beam; apolymeric rail extension attached to the vehicle rail on an end andattached to the bumper beam on another end, wherein the polymeric railextension comprises: a base extending from one end of the railextension, wherein the base includes vehicle rail attachments configuredto attach to the vehicle rail; a front member configured for attachmentto the bumper beam; a body extending from the base to the front member;an aperture extending through the base to the front member; and aconnection member attached to the bumper beam and extending through theaperture configured to attach the rail extension to the vehicle rail.

A method of forming a rail extension, includes: molding a first portion;molding a second portion; and joining the first portion and the secondportion; wherein the first portion and the second portion aresymmetrical about an axis of the rail extension; wherein the firstportion and the second portion comprise a base extending from one end ofthe rail extension having vehicle attachment configured to attach to avehicle rail; a front member configured for attachment to a bumper beam;and a body extending from the base to the front member.

A rail extension, includes: a base extending from an end of the railextension, wherein the base includes vehicle rail attachments configuredto attach to a vehicle rail; a front member configured for attachment toa bumper beam; a body extending from the base to the front member;wherein the body comprises reinforcing members; wherein the bodycomprises a first polymeric material; wherein the reinforcing memberscomprise a second polymeric material. The above described and otherfeatures are exemplified by the following figures and detaileddescription.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a brief description of the drawings wherein likeelements are numbered alike and which are presented for the purposes ofillustrating the exemplary embodiments disclosed herein and not for thepurposes of limiting the same.

FIG. 1 is an exploded view of a vehicle rail extension system.

FIG. 2 is an isometric front view of a polymeric rail extension.

FIG. 3 is an isometric rear view of the polymeric rail extension of FIG.2.

FIG. 4 is an isometric front view of a polymeric rail extension with ametallic or non-metallic rail attachment insert.

FIG. 5 is a front view of the polymeric rail extension of FIGS. 1 and 2.

FIG. 6 is a cross-sectional side view of a polymeric rail extension witha beam attachment insert taken along the line A-A of FIG. 5.

FIG. 7 is a cross-sectional top view of a polymeric rail extension witha beam attachment insert taken along the line B-B of FIG. 5.

FIG. 8A is a rear view of a polymeric rail extension.

FIG. 8B is an expanded view of the circled area in FIG. 8A.

FIG. 9 is a cross-sectional side view of a bumper beam, beam connectionplate, and polymeric rail extension.

FIG. 10 is an isometric exploded front view of polymeric rail extensionand a beam connection plate.

FIG. 11 is an isometric front view of polymeric rail extension and abeam connection plate.

FIG. 12 is a cross-sectional top view of a polymeric rail extensionhaving a progressive crush capability.

FIG. 13 is an isometric front view of a polymeric rail extension havingcrush initiators.

FIG. 14 is a top view of a polymeric rail extension having an angledfront member.

FIG. 15 is an exploded view of a vehicle rail extension system

FIG. 16 is an isometric rear view of a polymeric rail extension system.

FIG. 17 is an isometric rear view of another polymeric rail extensionsystem.

FIG. 18 is an isometric front view of a polymeric rail extension with ametallic connection member.

FIG. 19 is a front view of the metallic connection member of FIG. 18.

FIG. 20 is an isometric view of a symmetrical polymeric rail extension.

FIG. 21 is anisometric view of a portion of polymeric rail extensionwith reinforcing members.

FIG. 22 is an isometric view of a portion of another polymeric railextension with reinforcing members and an outer shell.

FIG. 23 is another isometric view of a portion of a polymeric railextension with reinforcing member, an outer shell, and a cover layer.

FIG. 24 is graphical representation of rail extension performanceshowing displacement (millimeters (mm)) versus force (kiloNewtons (kN))for simulated metallic and polymeric rail extensions.

FIG. 25 is graphical representation of rail extension performanceshowing displacement (mm) versus force (kN) for simulated metallic andpolymeric rail extensions.

FIG. 26 is graphical representation of rail extension performanceshowing displacement (mm) versus force (kN) for simulated polymeric railextensions with an anti-climber member and without an anti-climbermember.

FIG. 27 is graphical representation of rail extension performanceshowing displacement (mm) versus force (kN) for simulated polymeric railextensions with an anti-clasher member and without an anti-clashermember.

DETAILED DESCRIPTION

Disclosed herein, in various embodiments, are polymeric rail extensionsand rail extension systems which can be used in conjunction with vehiclecomponents (e.g., a bumper beam and vehicle rail), to minimize thedamage suffered during an impact. The polymeric rail extensions caninclude reinforcing members, shells, and outer layers to improve impactperformance. The rail extensions can be symmetrical about a horizontalor vertical axis passing through the center of the rail extension toreduce tooling costs. The polymeric rail extension systems can include ametallic connection member to improve impact performance, enable lowtowing, and improve high temperature performance. The polymeric railextensions can include a plate to prevent clashing (e.g., collision ofthe upper and lower portions) of the bumper beam during impact. Inaddition, the polymeric rail extensions can include a plate to preventslippage during impact. The rail extensions can be symmetrical about ahorizontal axis passing through the center of the rail extension toenable the rail extension to be used on either side of the vehicle.

The energy absorption section of the extensions are desirably configuredto, during impact, maintain a substantially constant force (e.g., willvary by less than or equal to 20%). In other words, if the desiredconstant force is 100 kiloNewtons (kN), the variation will not exceed 80kN to 120 kN. It is also noted, that, desirably, during an impact, theenergy absorption section imparts a force that exceeds the constantforce (e.g., the maximum desired force) by less than or equal to 20%.The energy absorption section imparts a force that exceeds the constantforce by less than or equal to 20%. The energy absorption sectionimparts a force that exceeds the constant force by less than or equal to10%. The energy absorption section imparts a force that exceeds theconstant force by less than or equal to 5%. In other words, if thedesired constant force is 100 kN, desirably, during an impact, theenergy absorption section imparts a force that is less than or equal to120 kN. The energy absorption section imparts a force that is less thanor equal to 110 kN. The energy absorption section imparts a force thatis less than or equal to 105 kN. It is understood that the forcesexerted by the energy absorption section are exerted during an impactsufficient to crush the energy absorption section, until the energyabsorption section is crushed.

In addition to maintaining a substantially constant force duringcrushing, the rail extension desirably crushes completely and does notexceed a force during crushing over the force limit for the vehicle. Theminimum force on the rail extensions that will initiate crushing isdependent upon the strength of the rails. Generally, the minimum forceto initiate crushing is greater than or equal to 60 kN, for example,greater than or equal to 70 kN, for example, greater than or equal to 80kN. In other words, the force during impact is maintained below theforce limit of the rails so that the rails do not fail or deform beforethe rail extensions fully crush.

The rail extensions can include a base, a body, and a front member. Thebase can be configured for attachment to a vehicle rail. The body canextend from the base to the front member. The base, body, and frontmember can be a unitary structure produced through an injection moldingprocess. As described herein, unitary refers to a structure wherein allcomponents are molded simultaneously. For example, the base, body, andfront member can be molded simultaneously to form a unity structure. Thebody can include cells defined by cell walls. Channels can be located onthe exterior of the body between the cells. For example, the cell wallscan form portions of a 3-sided channel that travels the length of thebody from the front member to the base. The channels can assist inensuring proper crushing of the rail extension.

An aperture can extend through the base, body, and front member. Theaperture can be sized to accommodate a connection member. The connectionmember can be metallic, carbon composite, or a combination including atleast one of the foregoing. The connection member can be directlyattached to the bumper beam, for example, mechanically or chemicallyattached. For example, the connection member can be welded, riveted,bolted, or adhesively joined to the bumper beam. Optionally, theconnection member can be attached to a plate attached to the bumperbeam. The connection member can include any cross-sectional geometry.For example, the connection member can have a round cross-section (e.g.,a tube having a geometric shape including, but not limited to, circular,oval, elliptical, pentagonal, hexagonal, heptagonal, octagonal,nonagonal, decagonal, etc.). The connection member can include one ormore crush initiators. The crush initiator can include holes,depressions, areas having thinned walls, grooves, and the like. Forexample, the crush initiator can include grooves having a “U-shaped,”“V-shaped,” semi-spherical shape, or other polygonal shape. The crushinitiators can be located at regular intervals along the body to inducebalanced crushing on all sides. In the alternative, the crush initiatorscan be located only at specific target areas in order to induce crushingalong a predetermined path. The connection member can include one ormore beam attachments that extend radially from the connection memberbetween the front member and the bumper beam and align with attachmentson the front member and/or the bumper beam.

The vehicle rail can include a rail attachment plate for connection tothe rail extensions and/or the connection member, e.g., via mechanicalor chemical attachment. The rail attachment plate can include a railattachment insert. The rail attachment insert can include internalthreading to accommodate a fastener (e.g., screw, bolt, and the like)for attachment to the connection member. For example, the railattachment insert can include a nut that is welded to the railattachment plate.

The rail extension can be symmetrical about a horizontal axis passingthrough the center of the rail extension. For example, from a frontalview, the rail extension can be symmetrical on a top half and a bottomhalf. In the alternative, the rail extension can be symmetrical along avertical axis passing through the center of the rail extension (e.g., aleft half and a right half). To facilitate the joining of a first halfand a second half, attachment features, such as protrusions andrecesses, tongue and groove, snap-fit, etc., can be formed on an outersurface of each half (e.g., where the two halves are to be joined). Theattachment features can include a complementary geometry, such asprotrusions and recesses and the like. The symmetry of the railextension provides an advantage in that only a single rail extensiondesign has to be manufactured for both the right hand and left handsides of the bumper beam (e.g., passenger and driver side). Thus, thesymmetrical rail extension eliminates the need for tooling and equipmentto manufacture multiple components with different geometries, e.g., aleft component and a right component. Accordingly, significant costs canbe eliminated by the symmetrical rail extension.

The base can extend perpendicular to the body. The base can include oneor more ribs that can extend from the base to a portion of the body. Theribs can be of any shape (e.g., rectangular, triangular, trapezoidal,and the like). The ribs can be structured to provide additional supportto the body. For example, the ribs can be placed in a particularlocation to provide for a controlled crushing direction.

The base can include attachments facilitating attachment to a vehiclerail. The attachments can be mechanical or chemical in nature, e.g., theattachments can be openings for accommodating a fastener (e.g., bolt,screw, and the like). The attachments can be attached through variousprocesses (e.g., vibration welding, adhesive, and the like). Theattachments can be of any shape. For example, the attachments can beround, elliptical, square, rectangular, or a combination comprising atleast one of the foregoing. An insert can be optionally located withinthe attachment. The insert can include a metallic material, polymericmaterial, or a combination of metallic and polymeric materials. Theinsert can advantageously add mechanical strength to the attachmentopening.

The front member can be formed integrally with the body and base to forma unitary structure. The front member can be perpendicular to the body.The front member can form an angle of 90° to 170° with the longitudinalaxis of the body. Thus, the front member can conform to a non-linearbumper beam. For example, the front member can be angled to accommodatea curved bumper beam. The front member can include one or more beamattachments. The beam attachments can extend from the front membertowards the base. The beam attachments can extend from the front memberto the base to facilitate the inclusion of a beam attachment insert. Forexample, the beam attachment can include a hollow passage that travelsfrom the front member to the base. Thus, the beam attachment insert canbe positioned through the base into the hollow passage and abut thefront member within the beam attachment. The beam attachment insert canbe included within the beam attachments. The beam attachment insert caninclude a metallic material, polymeric material, or a combination ofmetallic and polymeric materials. The beam attachment insert can includeinternal threading. Thus, a screw can be used to attach the front member(and optional plate) to the bumper beam. The front member can includeone or more tabs that extend outwardly from the front member to cover aportion of the channels. The tabs can include the beam attachments.

The body of the rail extension can include one or more crush initiators.The crush initiator can include holes, depressions, areas having thinnedwalls, grooves, and the like. For example, the crush initiator caninclude grooves having a “U-shaped,” “V-shaped,” semi-spherical shape,or other polygonal shape. The crush initiators can be located at regularintervals along the body to induce balanced crushing on all sides. Inthe alternative, the crush initiators can be located only at specifictarget areas in order to induce crushing along a predetermined path. Forexample, the crush initiators can be located only on one side of therail extension in order to direct crushing toward that side of the railextension.

The rail extensions can have multiple cells. The cells can be anypolygonal or rounded shape, such as circular, oval, square, rectangular,triangular, diamond, pentagonal, hexagonal, heptagonal, and octagonalgeometries as well as combinations comprising at least one of theforegoing geometries. Structures wherein the lengths of the sides areequal (besides a difference caused by the curvature of the angle formedby adjacent sides) can be useful in obtaining the desired crushcharacteristics. In other words, substantially square cells havingrounded or 90 degree corners can be useful.

Further tuning of the crush characteristics can be attained by bevelingthe outermost cells of the extension on two opposing sides to formchamfered cells. The beveling can be at an angle from the front memberof greater than 0° to 60°. The beveling can be at an angle from thefront member of 10° to 45°. The beveling can be at an angle from thefront member of 15° to 35°. The number of chamfered cells can bedependent upon the maximum force that can be exerted during a crash.Beveling cell(s) reduces the number of cells in physical contact withthe bumper and therefore reduces the initial force attained during animpact. The specific angle desired for a particular design can bedetermined by measuring the force transferred to the rails versusdisplacement upon a frontal crash, to determine if the maximum force isexceeded. As the angle increases, the initial force peak decreases.

All or some of the cells can travel the full length of the railextension (e.g., from the base to the front member or face). Inaddition, some cells can travel only a portion of the length of the railextension. For example, some cells can travel less than 75% of thedistance from the base to the front member. Some cells can travel lessthan 50% of the distance from the base to the front member. The cellscan have a cell wall geometry that progressively varies (e.g., becomesthicker or thinner) toward the base. The cells can have across-sectional shape that varies (e.g., increases or decreases) in areafrom the front member to the base. For example, the cells can have ageometry where the cells are narrowest toward the front member andwidest at the base. In the alternative, the cells can have constantcross-sectional shape from the front member to the base.

All or some of the cells can have a stepped geometry. In other words,the cells can increase in cross-sectional area from the front membertoward the base in incremental steps. Internal portions of the cells caninclude one or more ribs to add structural support. For example, when astepped geometry is employed, an internal rib can join one step to thenext within the cell structure. Thus, the rail extension canprogressively dissipate a portion of the kinetic energy through plasticdeformation and a programmed collapse starting from the front member tothe base.

The rail extension can include a plurality of reinforcement members. Thereinforcement members can vary in number from the base to the frontmember. For example, the base can include more reinforcement membersthan the front member. In addition, the type of reinforcement member canalso vary from the base to the front member. For example, the base caninclude an “X-shaped” rib structure, and the front member can include asimple vertical or horizontal rib. Thus, varying the type and number ofreinforcement structures within the body of the rail extension allowsfor tuning the stiffness of the body.

A plate can be attached to the front member and can be configured toattach to a bumper beam. The plate can be metallic, polymeric, or acombination of metallic and polymeric, e.g., a hybrid ofpolymeric/metallic material. The plate can include an anti-clash memberthat protrudes from the plate away in a direction away from the base.The anti-clash member can have a dimension that fits within a recess inthe beam. For example, the beam can include a “B-shaped” cross sectionand the anti-clash member can prevent the upper portion of the beam fromclashing (e.g., colliding with or impacting) with the lower portion ofthe beam. Thus, the beam can crush properly and energy absorption of thesystem can be improved. The plate can include an anti-climb member thatprotrudes from the plate toward the base. The anti-climb member can bedimensioned to fit within one or more cells of the rail extension,preventing slippage between the bumper beam and the rail extension. Bypreventing slippage during impact, the anti-climb member can increasethe impact absorption of the rail extension system. The plate can beattached to the rail extension and subsequently joined to the bumperbeam through welding, bolted joints, screwed joints or other fasteners.

The material of the rail extension can be any polymeric material orcombination of polymeric materials that can be formed into the desiredshape and provide the desired properties. Examples of polymericmaterials include thermoplastic materials as well as combinations ofthermoplastic materials elastomeric material, and/or thermosetmaterials. Possible thermoplastic materials include polybutyleneterephthalate (PBT); acrylonitrile-butadiene-styrene (ABS);polycarbonate; polycarbonate/PBT blends; polycarbonate/ABS blends;copolycarbonate-polyesters; acrylic-styrene-acrylonitrile (ASA);acrylonitrile-(ethylene-polypropylene diamine modified)-styrene (AES);phenylene ether resins; blends of polyphenylene ether/polyamide;polyamides; phenylene sulfide resins; polyvinyl chloride PVC; highimpact polystyrene (HIPS); low/high density polyethylene (L/HDPE);polypropylene (PP); expanded polypropylene (EPP); and thermoplasticolefins (TPO). For example, the polymer can comprise XENOY™ resin,and/or NORYL™ GTX resin, which are both commercially available fromSABIC's Innovative Plastics business. The polymer can optionally bereinforced, e.g., with fibers, particles, flakes, as well ascombinations comprising at least one of the foregoing. For example,glass fibers, carbon fibers, and combinations comprising at least one ofthe foregoing. For example, the plastic insert can be formed fromSTAMAX™ materials, a long glass fiber reinforced polypropylenecommercially available from SABIC SABIC's Innovative Plastics business.The extension can also be made from combinations comprising at least oneof any of the above-described materials and/or reinforcements, e.g., acombination with a thermoset material.

The rail extension can include multiple materials. For example, the bodycan include a first polymeric material. For example, the body caninclude polycarbonate, polyamide, polyphenylene ether, polybutyleneterephthalate, polyethylene terephthalate, and combinations including atleast one of the foregoing. The first polymeric material can includeless than or equal to 60% of a reinforcement material. The firstpolymeric material can be free from reinforcement material (e.g.,fillers, fibers, and the like), which can facilitate the use of ane-coating process for the rail extension.

Reinforcement materials can include any fillers typically used in theconventional compounding of polymers and thermoplastics can also beincluded in the masterbatch for dispersion into the polymeric matrixresin. Examples of such fillers well known in the art include thosedescribed in “Plastic Additives Handbook, 5th Edition” Hans Zweifel, Ed,Carl Hanser Verlag Publishers, Munich, 2001. Non limiting examples offillers include silica powder, such as fused silica and crystallinesilica; boron-nitride powder and boron-silicate powders for obtainingcured products having low dielectric constant and low dielectric losstangent; alumina, and magnesium oxide (or magnesia) for high temperatureconductivity; and fillers, such as wollastonite including surfacetreated wollastonite, calcium sulfate (as its anhydride, dihydrate ortrihydrate), calcium carbonate including chalk, limestone, marble andsynthetic, precipitated calcium carbonates, generally in the form of aground particulates; talc, including fibrous, modular, needle shaped,and lamellar talc; glass spheres, both hollow and solid; kaolin,including hard, soft, calcined kaolin, and kaolin comprising variouscoatings known in the art to facilitate compatibility with the polymericmatrix resin; mica, feldspar, silicate spheres, flue dust, cenospheres,fillite, aluminosilicate (armospheres), natural silica sand, quartz,quartzite, perlite, tripoli, diatomaceous earth, synthetic silica, andthe like. All of the above fillers may be coated with a layer ofmetallic material to facilitate conductivity or surface treated withsilanes to improve adhesion and dispersion with the polymeric matrixresin. Glass fibers, including textile glass fibers such as E, A, C,ECR, R, S, D, and NE glasses and quartz, and the like may also be addedinto the masterbatch. In addition, organic reinforcing fibrous fillersmay also be including, organic polymers capable of forming fibers.

An outer shell can be located around at least a portion to the railextension and can include a material that is different from or the sameas the first and/or second polymeric material. For example, the outershell can include a metallic material, carbon fiber reinforced polymericmaterial, glass fiber reinforced polymeric material, and combinationsincluding at least one of the foregoing. An outer layer comprising thefirst or second polymeric material can be located on an external surfaceof the outer shell.

A method of making a rail extension can include molding a first portionand second portion. The first and second portions can be identical(e.g., made from the same mold cavity). In addition, first and secondportions can be symmetrical about a vertical or horizontal axis. Thefirst and second portions can include a base, body, and front member. Inaddition, the first and second portions can include one or morereinforcement members. Molding and joining identical mold portions canadvantageously reduce tooling costs and can allow customization of thestiffness of the rail extension. For example, reinforcing members can bemolded within the first and second portion. The reinforcing members canbe varied in both stiffness and geometry. For example, the reinforcingmembers can be made less stiff at the front member and can have aprogressively greater stiffness toward the base. An outer shell can beovermolded onto the first and second portions. An additional outer layercan be formed over the outer shell. For example, the outer layer can beovermolded onto the outer shell. The first and second portions can bejoined through chemical and/or mechanical attachments, e.g., adhesive,vibration welding, and other similar processes.

The rail extensions described herein can be formed through an additivemanufacturing process. For example, a rail extension can be formedthrough Material Extrusion, Fused Deposition Modeling (FDM) or FusedFilament Fabrication (FFF), Selective Laser Sintering (SLS), DirectMetal Laser Sintering (DMLS), Electron Beam Freeform Fabrication (EBF³),Electron Beam Melting (EBM), Laminated Object Manufacturing (LOM),Stereolithography (SLA), and Digital Light Processing (DLP).

The overall size, e.g., the specific dimensions of the rail extensionwill depend upon the particular vehicle, the desired crushcharacteristics, and the space available. For example, the length (1),height (h), and width (w) of the rail extension, will depend upon theamount of space available between the rail and the bumper beam of thevehicle as well as crush characteristics (e.g., desired displacement,force). The design of the cells, the angle and existence of chamferedsection, and the thickness of the cell walls will depend upon thedesired crush characteristics (e.g., maximum force exerted by the railextension during an impact (e.g., while crushing)). The length, l, ofthe rail extension can be less than or equal to 300 mm, for example, 50mm to 250 mm, and for example 100 mm to 200 mm (e.g., 150 mm). Thewidth, w, of the energy absorbing device can be less than or equal to200 mm, for example, 20 mm to 150 mm, and for example 40 mm to 100 mm.The height, h, of the energy absorbing device can be less than or equalto 300 mm, for example, 60 mm to 200 mm, and for example 80 mm to 150mm. The length is greater than or equal to the height which is greaterthan or equal to the width. The length, height, and width measurementsare the broadest measurement in the specified direction, excludingvehicle attachment tabs. The thickness of the cell walls can be up to7.0 mm, for example, 2.0 mm to 6.0 mm, and for example, 3.0 mm to 5.0mm.

As with the dimensions of the components, the number of cells isdependent upon the desired stiffness, crush characteristics, andmaterials employed. For example, the rail extension can have up to 4cells. The rail extension can have 4 to 25 cells. The rail extension canhave less than or equal to 50 cells.

The rail extensions disclosed herein are configured to absorb asignificant amount of impact energy when subjected to axial loadingwhile also having acceptable creep performance (i.e., less deformationupon impact). For example, the rail extension can have a creepperformance when subjected to 4.5 MegaPascals (MPa) stress loading for600 hours at 90° C. of negligible deformation (e.g., less than or equalto 5 mm, for example, less than or equal to 3 mm, and for example, lessthan or equal to 1 mm).

FIG. 1 illustrates a rail extension system 16. As shown in FIG. 1, arail extension system can include vehicle rail 60 coupled to one end 72of rail extension 1. Bumper beam 20 is coupled to an opposite end 74 ofrail extension 1. Energy absorber 64 can be configured to attach to aportion of bumper beam 20. Fascia 66 can cover energy absorber 64 andbumper beam 20. FIG. 2 illustrates the rail extension 1 including base2, body 5 extending from base 2 and toward front member 4. The railextension 1 can include a polymeric material. As shown in FIG. 2, base 2can include ribs 15 extending from a body facing surface 73 of base 2 toan outer surface 75 of body 5. The ribs 15 can include anycross-sectional shape that will provide the desired stiffness. Forexample, the ribs 15 can include a shape selected from triangular,rectangular, parabolic, or a combination comprising at least one of theforegoing. In addition, base 2 can include rail attachments 3 tofacilitate attachment to a vehicle rail. Base 2 can include featuressuch as notch 13 located at a top 76 and bottom 77 of base 2. The notch13 can be symmetrical about a horizontal axis to facilitate the use of asingle tool to produce both left and right rail extensions. Body 5 caninclude a plurality of cells 6, e.g., first cells 6 a, that can extendfrom base 2, through body 5 to front member 4. Channels 7 can be locatedbetween adjacent cells 6. Front member 4 can include bumper beamattachments 8 to facilitate attachment of rail extension 1 to a bumperbeam. Beam attachment 8 extends towards base 2 through front member 4.Beam attachment 8 can extend through a portion of the body 5. Beamattachment 8 can extend through the entirety of the body 5.

FIG. 3 illustrates a rear view of the rail extension 1 of FIG. 2. FIG. 3is one possibility for the rear of rail extension 1 of FIG. 2. As can beseen in FIG. 3, rail attachments 3 extend through base 2. FIG. 3 furtherillustrates that the cells 6 can include a first cell 6 a and a secondcell 6 b, where first cell 6 a can extend from base 2, completelythrough body 5 to front member 4 (see FIG. 2) and second cell 6 b canextend from base 2 and partially through body 5. Channels 7 locatedbetween adjacent first cells 6 a are illustrated in FIG. 3. Notches 13are illustrated as extending toward base 5. FIG. 4 illustrates the railextension 1 of FIG. 2 including rail attachment insert 25. As shown inFIG. 4, base 2 can include ribs 15 extending from a body facing surface73 of base 2 to an outer surface 75 of body 5. Ribs 15 can assist inguiding the crushing of the rail extension 1 smoothly. The ribs 15 caninclude any cross-sectional shape that will provide the desiredstiffness. For example, the ribs 15 can include a shape selected fromtriangular, rectangular, parabolic, or a combination comprising at leastone of the foregoing. In addition, base 2 can include rail attachments 3to facilitate attachment to a vehicle rail. Base 2 can include featuressuch as notch 13 located at a top 76 and bottom 77 of base 2. The notch13 can be symmetrical about a horizontal axis to facilitate the use of asingle tool to produce both left and right rail extensions. Body 5 caninclude a plurality of cells 6, e.g., first cells 6 a, that can extendfrom base 2, through body 5 to front member 4. Front member 4 caninclude aperture 78. Channels 7 can be located between adjacent cells 6.Front member 4 can include bumper beam attachments 8 to facilitateattachment of rail extension 1 to a bumper beam. Beam attachment 8extends towards base 2 through front member 4. Beam attachment 8 canextend through a portion of the body 5. Beam attachment 8 can extendthrough the entirety of the body 5. As shown in FIG. 4, each railattachment 3 can include rail attachment insert 25. The size of railattachment insert 25 can vary to accommodate varying mechanicalfasteners. For example, rail attachment insert 25 can be sized to fit abolt, screw, or similar fastener. Rail attachment insert 25 can reducethe stress on the rail extension due to the attachment to the vehicle.Optionally, rail attachment insert 25 can be a metallic material or adifferent polymeric material than the cells. For example, railattachment insert 25 can include a metallic material, such as steel.

FIG. 5 is a front view of the rail extension 1 of FIGS. 2 and 4. As canbe seen in FIG. 5, rail extension 1 includes base 2 with a notch 13located at a top 76 and bottom 77 of base 2. The notch 13 can besymmetrical about a horizontal axis to facilitate the use of a singletool to produce both left and right rail extensions. Body 5 (see FIG. 2or FIG. 4) can include a plurality of cells 6, e.g., first cells 6 a,that can extend from base 2, through body 5 to front member 4. Cells 6can terminate at front member 4. Base 2 can include ribs 15 and railattachments 3. Channels 7 can be located between adjacent cells 6. Frontmember 4 can include bumper beam attachments 8 to facilitate attachmentof rail extension 1 to a bumper beam. Beam attachment 8 extends towardsbase 2 through front member 4. Beam attachment 8 can extend through aportion of the body 5. Beam attachment 8 can extend through the entiretyof the body 5 (see FIG. 4).

FIG. 6 is a cross-sectional side view of the rail extension 1 of FIG. 5taken along the line A-A. FIG. 7 is a cross-sectional top view of therail extension 1 of FIG. 5 taken along the line B-B. As shown in FIGS. 6and 7, beam attachments 8 can include beam attachment insert 27. Beamattachment insert 27 can include a metallic material, polymericmaterial, or a combination of metallic and polymeric materials. Inaddition, beam attachment insert 27 can include threading to accommodatea screw for attachment to a bumper beam. First cell 6 a and second cell6 b are further illustrated in FIG. 6. As can be seen in FIG. 6, firstcell 6 a can extend from base 2, completely through body 5 to frontmember 4. Second cell 6 b can extend from base 2, partially through body5, terminating before reaching front member 4. Second cell 6 b caninclude protrusion 9 extending toward the front member 4, butterminating before reaching the front member 4, so that protrusion 9 isnot visible in a front view of rail extension 1. Protrusion 9 can beparallel to beam attachment insert 27 and can assist in providingstructural integrity to the cells 6.

FIGS. 8A and 8B illustrate another rear view of rail extension 1 (e.g.,a polymeric rail extension). As can be seen in FIG. 8A, rail attachments3 extend through base 2. FIG. 8A further illustrates that the cells 6can include a first cell 6 a and a second cell 6 b, where first cell 6 acan extend from base 2, completely through body 5 (see FIG. 2) to frontmember 4 (see FIG. 2) and second cell 6 b can extend from base 2 andpartially through body 5. Beam attachments 8 can be isolated withinfirst cell 6 a. As shown in FIG. 8A, base 2 can include notches 13,which can be located on a top surface 76 and a bottom surface 77 of thebase 2, where the notches can be symmetrical about a horizontal axis tofacilitate the use of a single tool to produce both left hand and righthand rail extensions. FIG. 8A illustrates ribs 30 located in upper andsecond cells 6 a, 6 b. FIG. 8B is an expanded view of the circle areashown in FIG. 8A. As shown in FIG. 8B, rib 30 can be located in secondcell 6 b. Rib 30 can provide structural integrity to the cells 6 a, 6 b.

FIG. 9 illustrates plate 10 including anti-climbing member 12 andanti-clashing member 14. Plate 10 can include a metallic materialpolymeric material, or a combination of metallic and polymericmaterials. As shown in FIG. 9, anti-climbing member 12 projects towardbase 2 and can be sized to fit within cell 6. Plate 10 can include morethan one anti-climbing member 12. Anti-clashing member 14 projects awayfrom base 2 and into a recess 22 in bumper beam 20. For example, whenbumper beam 20 includes a “B-shaped” or “C-shaped” cross-section,anti-clashing member 14 can protrude into a recess 20 formed by upperand lower portions of beam 20. The beam 20 in FIG. 9 can be “B-shaped”and include upper portion 23 and lower portion 24 separated by recess22. Anti-clashing member 14 can prevent clashing of upper section 23 andlower portion 24 during an impact to ensure proper crushing and energyabsorption. Plate 10 can be joined to bumper beam 20 through welding,adhesive, mechanical fasteners, and the like, e.g., anti-climbing membercan be inserted into cell 6 and plate 10 can be welded to beam 20.

FIG. 10 illustrates rail extension 11. Body 5 extends from base 2 towardfront member 4. Rail attachments 3 can be located in base 2 to assist inattaching the base 2 to a vehicle rail. Ribs 15 can extend from base 2and be located on body 5 to assist in guiding crushing during an impact.Cells 6 located in base 5 can include a beveled edge. The beveling canbe at an angle from front member 4 of greater than 0° to 60°. Thebeveling can be at an angle from front member 4 of 10° to 45°. Thebeveling can be at an angle from front member 4 of 15° to 35°. Railextension 11 can include plate 40. As shown in FIG. 10, plate 40 caninclude plate attachment openings 41 configured to align with beamattachment openings 8. Thus, plate 40 can be attached to a bumper beamand front member 4 by a mechanical fastener such as a bolt, screw, andthe like. Plate 40 can include one or more projections 42 that canoverlap a top and/or bottom surface of a bumper beam. Thus, projections42 can serve to prevent slippage between the bumper beam and the railextension during impact.

FIG. 11 illustrates rail extension 1 with body 5 extending from base 2toward front member 44. The rail extension 1 can include a polymericmaterial. As shown in FIG. 11, base 2 can include ribs 15 extending froma body facing surface 73 of base 2 to an outer surface 75 of body 5. Theribs 15 can include any cross-sectional shape that will provide thedesired stiffness. For example, the ribs 15 can include a shape selectedfrom triangular, rectangular, parabolic, or a combination comprising atleast one of the foregoing. In addition, base 2 can include railattachments 3 to facilitate attachment to a vehicle rail. Base 2 caninclude features such as notch 13 located at a top 76 and bottom 77 ofbase 2. The notch 13 can be symmetrical about a horizontal axis tofacilitate the use of a single tool to produce both left and right railextensions. Body 5 can include a plurality of cells 6 that can extendfrom base 2, through body 5 to front member 44. Front member 44 coverscells 6 in FIG. 11. Channels 7 can be located between adjacent cells 6.Front member 44 can include bumper beam attachments 8 to facilitateattachment of rail extension 1 to a bumper beam. Beam attachment 8extends towards base 2 through front member 44. Beam attachment 8 canextend through a portion of the body 5. Beam attachment 8 can extendthrough the entirety of the body 5. FIG. 11 further illustrates anothermechanism that can be used to attach the rail extension 1 to a beam. Asshown in FIG. 11, tabs 50 extend from front member 44 between cells 6.In other words, tab 50 can extend into and cover a portion of channel 7.Each tab 50 includes a beam attachment 8 that can accommodate a fastenersuch as a bolt, screw, and the like. Tab 50 can include a reinforcinginsert made from a metallic material, polymeric material, or acombination of metallic and polymeric material.

FIG. 12 illustrates a top cross-sectional view of a rail extension, forexample, rail extension 1 or rail extension 11. As shown in FIG. 12, anouter surface 75 of body 5 can include one or more steps 35 thatprogressively become wider toward base 2. An internal rib 33 can jointwo adjacent steps 35 to provide additional stiffness to the railextension. Thus, the rail extension can progressively dissipate aportion of the kinetic energy through plastic deformation and aprogrammed collapse starting from front member 4 to base 2. FIG. 13illustrates an isometric side view of a rail extension 31 with crushinitiators 70. FIG. 13 illustrates rail extension 31 with body 5extending from base 2 toward front member 4. The rail extension 31 caninclude a polymeric material. As shown in FIG. 13, base 2 can includeribs 15 extending from a body facing surface 73 of base 2 to an outersurface 75 of body 5. The ribs 15 can include any cross-sectional shapethat will provide the desired stiffness. For example, the ribs 15 caninclude a shape selected from triangular, rectangular, parabolic, or acombination comprising at least one of the foregoing. In addition, base2 can include rail attachments 3 to facilitate attachment to a vehiclerail. Base 2 can include features such as notch 13 located at a top 76and bottom 77 of base 2. The notch 13 can be symmetrical about ahorizontal axis to facilitate the use of a single tool to produce bothleft and right rail extensions. Body 5 can include a plurality of cells6, e.g., first cell 6 a, that can extend from base 2, through body 5 tofront member 4. Front member 4 covers cells 6 in FIG. 11. Channels 7 canbe located between adjacent cells 6. Front member 4 can include bumperbeam attachments 8 to facilitate attachment of rail extension 1 to abumper beam. Beam attachment 8 extends towards base 2 through frontmember 4. Beam attachment 8 can extend through a portion of the body 5.Beam attachment 8 can extend through the entirety of the body 5. Asshown in FIG. 13, crush initiator 70 can include a groove 71 formed inone or more sides of body 5. The groove can include a “V-shaped,”“U-shaped,” semi-sphere shape or other polygonal geometry. Crushinitiator 70 can include an area of thinner material than the remainderof body 5. In the alternative, crush initiator 70 can include one ormore holes in the walls of body 5. Crush initiators 70 can be spaced atregular intervals. One or more sides of body 5 can include crushinitiators 70. Front member 4 can further include aperture 78.

FIG. 14 illustrates a top view of a rail extension as disclosed hereinwith a front member 4 having an angled surface with a base 2 attached toa rail 60. As shown in FIG. 14, front member 4 includes an angledsurface to accommodate a curved bumper beam 20. Front member 4 can forman angle α of greater than 90° up to 170° with the longitudinal axis “A”of body 5. Front member 4 can include a flat surface (e.g., 90° to thelongitudinal axis “A” of body 5) to accommodate a flat bumper beam 20.FIG. 15 illustrates a rail extension system 17. As shown in FIG. 15, arail extension system 17 can include vehicle rail 60 coupled to one endof rail extension 1. The rail extension 1 can include base 2, body 5,and front member 4 with rail attachments 3 located on base 2 and bolts79 to assist in attaching the rail extension 1 to the vehicle rail 60.Ribs 15 can extend from a body facing surface 73 of the base 2configured to assist in crushing during an impact. Body 5 can include aplurality of cells 6 a that can extend from base 2, through body 5 tofront member 4. Front member 4 covers cells 6 b in FIG. 15. Channels 7can be located between adjacent cells 6 a. Front member 4 can includebumper beam attachments 8 to facilitate attachment of rail extension 1to a bumper beam. Beam attachment 8 extends towards base 2 through frontmember 4. Beam attachment 8 can extend through a portion of the body 5.Beam attachment 8 can extend through the entirety of the body 5.Aperture 100 can extend the length of the rail extension 1 from frontmember 4 to base 2 through body 5. Connection member 102, present onbumper beam 20, is configured to fit within aperture 100. Connectionmember 102 can include one or more crush initiators 114 to inducecrushing of the connection member 102 during impact. Connection member102 can be welded to bumper beam 20. Bumper beam 20 can include anaccess point 21 for inserting fastener 103 to join connection member 102to vehicle rail 60. Vehicle rail 60 can include a rail attachment plate61. Rail attachment plate 61 can be made from a metallic material andwelded to vehicle rail 60. Rail attachment insert 62 can be locatedwithin rail attachment plate 61 and can include internal threading forreceiving fastener 103.

FIG. 16 illustrates a rear view of the rail extension system 17 of FIG.15. As can be seen in FIG. 16, rail attachments 3 extend through base 2.FIG. 16 further illustrates that the cells 6 can include a first cell 6a and a second cell 6 b, where first cell 6 a can extend from base 2,completely through body 5 to front member 4 (see FIG. 15) and secondcell 6 b can extend from base 2 and partially through body 5. Channels 7located between adjacent first cells 6 a are illustrated in FIG. 16.Notches 13 are illustrated as extending toward base 5. As shown in FIG.16, fastener 103 protrudes through an end of connection member 102.Fastener 103 then protrudes through rail attachment plate 61 to providea metal to metal connection between the bumper beam 20, connectionmember 100, fastener 103, and vehicle rail 60. Thus, the rail extensionsystem 17 can withstand high temperatures and towing. In addition, theneed to use a conductive material for the rail extension is eliminated.

FIGS. 17 and 18 illustrate examples of joining connection member 100 toa rail extension where the rail extension includes a base 2 and body 5extending from the base 2 and a bumper beam. As shown in FIGS. 17 and18, beam attachments 104 extend radially from connection member 100 atfront member 4, where beam attachments 104 cover front member 4. Forexample, beam attachments 104 can include tabs 80 with holes 82configured to receive a fastener. Thus, beam attachments 104 can alignwith beam attachments 8 (see FIG. 2) on the rail extension to join abumper beam, connection member 100, and rail extension. FIG. 19illustrates a front view of a rail extension including two symmetricalportions 106, 108. As show in FIG. 19, the two portions 106 and 108 aresymmetrical about a vertical axis of the rail extension. It is to beunderstood, however that portions 106 and 108 can be symmetrical about ahorizontal axis. Accordingly, a single mold cavity can produce firstportion 106 and second portion 108. First portion 106 and second portion108 can be joined by vibration welding, adhesive, or other similarprocesses. To facilitate the joining of first portion 106 and secondportion 108, attachment features such as protrusion 115 and recess 116can be formed on an outer surface of each portion. The attachmentfeatures can include any complementary geometry. First portion 106 andsecond portion 108 can include one or more reinforcing members 112.

FIG. 20 illustrates a portion of multi-material rail extension 90. Asshown in FIG. 20, body 5 can be made from a first polymeric material andreinforcement members 112 can be made from a second polymeric material.In addition, reinforcing members 112 can vary from front member 4 tobase 2. Beam attachments 8 can extend outwardly from the front member 4.As shown in FIG. 20, the number of reinforcing members 112 increasesfrom front member 4 to base 2. In addition, the type of reinforcingmember can vary from front member 4 to base 2. As shown in FIG. 20,reinforcing members 112 adjacent base 2 can have an “X-shaped”structure. Reinforcing member 112 adjacent front member 4 can havesimple horizontal rib structure. Thus, the rail extension can have agreater stiffness at base 2 than at front member 4.

FIG. 21 illustrates another portion of a multi-material rail extension92. As shown in FIG. 21, outer shell 110 surrounds portions of the railextension. Outer shell 110 can include a different material than thefirst polymeric material and the second polymeric material. For example,outer shell 110 can include a metallic material, carbon fiber reinforcedpolymeric material, glass fiber reinforced polymeric material, andcombinations including at least one of the foregoing. Outer shell 110can be overmolded onto portions of the rail extension. FIG. 22illustrates another portion of a multi-material rail extension 94. Asshown in FIG. 22, outer layer 113 can be added externally to the outershell 110. Outer layer 113 can include the first polymeric material, thesecond polymeric material, or another polymeric material. Outer layer113 can be overmolded onto outer shell 110.

As with FIG. 20, reinforcing members 112 in FIGS. 21 and 22 can varyfrom front member 4 to base 2. Beam attachment(s) 8 can extend outwardlyfrom the front member 4. As shown in FIGS. 21 and 22, the number ofreinforcing members 112 increases from front member 4 to base 2 alongbody 5. In addition, the type of reinforcing member can vary from frontmember 4 to base 2. As shown in FIGS. 21 and 22, reinforcing members 112adjacent base 2 can have an “X-shaped” structure. Reinforcing member 112adjacent front member 4 can have simple horizontal rib structure. Thus,the rail extension can have a greater stiffness at base 2 than at frontmember 4.

FIG. 23 illustrates another rear view of the rail extension system 17 ofFIG. 15. As can be seen in FIG. 23, fastener 103 protrudes through anend of connection member 102 and rail attachment insert 62. Reinforcingmember 96 attaches to vehicle rail 60 with rail attachment plate 61attached thereto. Fastener 103 then protrudes through rail attachmentplate 61 to provide a metal to metal connection between the bumper beam20, connection member 100, fastener 103, and vehicle rail 60. Thus, therail extension system 17 can withstand high temperatures and towing. Inaddition, the need to use a conductive material for the rail extensionis eliminated.

Any of the rail extensions or rail extension systems can be made byAdditive Manufacturing (AM) which is a new production technology thatmakes three-dimensional (3D) solid objects of virtually any shape from adigital model. Generally, this is achieved by creating a digitalblueprint of a desired solid object with computer-aided design (CAD)modeling software and then slicing that virtual blueprint into verysmall digital cross-sections. These cross-sections are formed ordeposited in a sequential layering process in an AM machine to createthe 3D object.

EXAMPLES

FIGS. 24-27 are graphic illustrations of displacement versus force for asimulated impact. The design of the simulations is for a 15 kilometerper hour (kmph) 40% offset RCAR impact of a pendulum against an assemblyof a rail extension system. The intrusion is measured as thedisplacement of the pendulum and the force as that experienced by therail extension on the side of impact. FIG. 24 illustrates the use of apolymeric rail extension directly joined to the bumper beam as shown inFIG. 2. As shown in FIG. 24, the polymeric rail extension (B) producesan intrusion similar to steel rail (A) extension while reducing partcount. A blend of polyamide (PA) and polyphenylene ether polymer (PPE)is used (e.g., NORYL™ GTX™ resin, commercially available from SABIC'sInnovative Plastics business). FIG. 25 illustrates the use of apolymeric rail extension including a plate having both an anti-clasherand an anti-climber as illustrated in FIG. 9. As shown in FIG. 25, thepolymeric rail extension (B) produced a reduction in intrusion comparedto a steel rail extension (A). A blend of polyamide (PA) andpolyphenylene ether polymer (PPE) is used (e.g., NORYL™ GTX™ resin,commercially available from SABIC's Innovative Plastics business).

FIG. 26 illustrates the results of an impact on a polymeric railextension without an anti-climber (A) and a polymeric rail extensionwith an anti-climber (B). As shown in FIG. 26, the polymeric railextension with an anti-climber resulted in a reduction in intrusion of 2mm. A blend of polyamide (PA) and polyphenylene ether polymer (PPE) isused (e.g., NORYL™ GTX™ resin, commercially available from SABIC'sInnovative Plastics business). FIG. 27 illustrates the results of animpact on a polymeric rail extension without an anti-clasher (A) and apolymeric rail extension with an anti-clasher (B). As shown in FIG. 27,the polymeric rail extension with an anti-clasher resulted in areduction in intrusion of 5 mm. A blend of polyamide (PA) andpolyphenylene ether polymer (PPE) is used (e.g., NORYL™ GTX™ resin,commercially available from SABIC's Innovative Plastics business).

Set forth below are some embodiments of the rail extension, railextension systems vehicles comprising the rail extensions, or railextension systems and methods of making the same.

Embodiment 1

A rail extension, comprising: a base extending from one end of the railextension, wherein the base includes vehicle rail attachments configuredto attach to a vehicle rail; a front member configured for attachment toa bumper beam; a body extending from the base and toward the frontmember, wherein the base comprises cells formed by cell walls extendingalong at least a portion of a length of the body from the base towardthe front member and forming cavities therethrough; open channels formedon each side of the body, wherein the open channels are defined by wallsof adjacent cells; wherein the front member comprises a plurality ofbeam attachments that extend from the front member towards the base; andbeam attachment inserts located within the beam attachments.

Embodiment 2

The rail extension of Embodiment 1, further comprising rail attachmentinserts located within the rail attachments.

Embodiment 3

The rail extension of Embodiment 1 or Embodiment 2, further comprising aplate coupled to the front member, wherein the plate comprises ananti-climbing member extending toward the base and sized to fit within acell and an anti-clashing member extending away from the base andconfigured to fit within a recess of the bumper beam.

Embodiment 4

The rail extension of any of Embodiments 1-3, wherein the cells extendan entire length of the body.

Embodiment 5

The rail extension of any of Embodiments 1-4, wherein the front membercomprises an insert having internal threading for receiving a fastener.

Embodiment 6

The rail extension of any of Embodiments 1-5, wherein the rail extensionis symmetrical about a horizontal line passing through a center of therail extension.

Embodiment 7

The rail extension of any of Embodiments 1-6, wherein the base furthercomprises metal inserts located within the rail attachments.

Embodiment 8

The rail extension of any of Embodiments 1-7, wherein the base comprisesat least one rib extending from a body facing surface of the base to anoutside surface of the body.

Embodiment 9

The rail extension of any of Embodiments 1-8, wherein a cross-sectionalarea of a cell varies from the front member to the base.

Embodiment 10

The rail extension of any of Embodiments 1-9, wherein a thickness of atleast a portion of the cell wall varies from the front member to thebase.

Embodiment 11

The rail extension of any of Embodiments 1-3 and 5-10 wherein at leastsome of the cells do not extend the length of the body from the base tothe front member.

Embodiment 12

The rail extension of any of Embodiments 1-11, wherein the cells have across-sectional geometry comprising circular, elliptical, polygonalshapes, and combinations including at least one of the foregoing.

Embodiment 13

The rail extension of any of Embodiments 1-12, wherein the bodyincreases in cross-sectional area in a stepped geometry from the frontmember to the base.

Embodiment 14

The rail extension of any of Embodiments 1-13, wherein the railextension comprises a polymeric material, metallic material, orcombination comprising at least one of the foregoing.

Embodiment 15

The rail extension of any of Embodiments 1-14, wherein the railextension comprises polybutylene terephthalate;acrylonitrile-butadiene-styrene; polycarbonate; polycarbonate/PBTblends; polycarbonate/ABS blends; copolycarbonate-polyesters;acrylic-styrene-acrylonitrile; acrylonitrile-(ethylene-polypropylenediamine modified)-styrene; phenylene ether resins; blends ofpolyphenylene ether/polyamide; polyamides; phenylene sulfide resins;polyvinyl chloride; high impact polystyrene; low/high densitypolyethylene; polypropylene; expanded polypropylene; thermoplasticolefins; and combinations including at least one of the foregoing.

Embodiment 16

The rail extension of any of Embodiments 1-15, wherein a cell includesan internal rib.

Embodiment 17

The rail extension of any of Embodiments 1-16, wherein the base, body,and front member form a unitary structure.

Embodiment 18

The rail extension of any of Embodiments 1-17, wherein cells adjacent tochannels on two opposing sides of the body have a beveled surface.

Embodiment 19

The rail extension of Embodiment 18, wherein the beveled surface has achamfer angle of greater than 0 to 60°.

Embodiment 20

The rail extension of Embodiment 18, wherein the chamfer angle isgreater than 10° to 45°.

Embodiment 21

The rail extension of any of Embodiments 1-20, wherein the front membercomprises an angled surface.

Embodiment 22

The rail extension of any of Embodiments 1-21, wherein the bodycomprises a crush initiator.

Embodiment 23

The rail extension of any of Embodiments 1-22, wherein the basecomprises a rib extending from the base to an outer surface of the body.

Embodiment 24

The rail extension of any of Embodiments 1-23, further comprising ananti-climbing member coupled to the front member and extending into acell.

Embodiment 25

The rail extension of any of Embodiments 1-24, further comprising a tabextending from the front member into a channel, wherein the tabcomprises a beam attachment.

Embodiment 26

A method of making a rail extension of any of Embodiments 1-25, whereinthe rail extension is formed through an extrusion or injection moldingprocess.

Embodiment 27

A vehicle comprising: a bumper beam; a vehicle rail; and the railextension of any of Embodiments 1-26 coupled to the bumper beam and thevehicle rail.

Embodiment 28

A rail extension system, comprising: a vehicle rail; a bumper beam; apolymeric rail extension attached to the vehicle rail on an end andattached to the bumper beam on another end, wherein the polymeric railextension comprises: a base extending from one end of the railextension, wherein the base includes vehicle rail attachments configuredto attach to the vehicle rail; a front member configured for attachmentto the bumper beam; a body extending from the base to the front member;an aperture extending through the base to the front member; and aconnection member attached to the bumper beam and extending through theaperture configured to attach the rail extension to the vehicle rail.

Embodiment 29

The rail extension system of Embodiment 28, wherein the connectionmember further comprises bumper beam attachments extending from theconnection member and configured for attachment to the bumper beam andthe front member.

Embodiment 30

The rail extension system of Embodiment 28 or Embodiment 29, furthercomprising a rail attachment plate attached to the vehicle rail; whereinthe rail attachment plate comprises a rail attachment insert; and afastener configured to attach the connection member to the railattachment insert.

Embodiment 31

The rail extension system of any of Embodiments 28-30, wherein theconnection member is attached directly to the bumper beam throughwelding, riveting, bolting or adhesive.

Embodiment 32

The rail extension system of any of Embodiments 28-31, wherein theconnection member comprises a metallic material or a composite material.

Embodiment 33

The rail extension system of any of Embodiments 28-32, wherein the railattachment insert comprises an internal threading configured to receivethe fastener.

Embodiment 34

The rail extension system of any of Embodiments 28-33, where in theconnection member further comprises a crush initiator.

Embodiment 35

The rail extension system of any of Embodiments 28-34, wherein the railextension is overmolded onto the connection member.

Embodiment 36

A method of forming a rail extension, comprises: molding a firstportion; molding a second portion; and joining the first portion and thesecond portion; wherein the first portion and the second portion aresymmetrical about an axis of the rail extension; wherein the firstportion and the second portion comprise a base extending from one end ofthe rail extension having vehicle attachment configured to attach to avehicle rail; a front member configured for attachment to a bumper beam;and a body extending from the base to the front member.

Embodiment 37

The method of Embodiment 36, wherein the first portion and the secondportion comprise a first polymeric material overmolded onto a secondpolymeric material.

Embodiment 38

The method of Embodiment 36 or Embodiment 37, further comprising anouter shell located around at least a portion of the rail extension.

Embodiment 39

The method of any of Embodiments 36-38, wherein the first portion andthe second portion comprise reinforcing members.

Embodiment 40

The method of Embodiment 37, wherein the reinforcing members comprise adifferent polymeric material or the same polymeric material as the firstportion and the second portion.

Embodiment 41

The method of any of Embodiments 37-40, wherein the first polymericmaterial comprises polycarbonate, polyamide, polyphenylene ether,polybutylene terephthalate, polyethylene terephthalate, and combinationsincluding at least one of the foregoing.

Embodiment 42

The method of any of Embodiments 37-41, wherein the second polymericmaterial comprises a reinforced polymeric material.

Embodiment 43

The method of Embodiment 38, wherein the outer shell comprises ametallic material, carbon fiber reinforced polymeric material, glassfiber reinforced polymeric material, and combinations including at leastone of the foregoing.

Embodiment 44

The method of any of Embodiments 36-43, wherein the first portion andthe second portion are symmetrical along a vertical axis of the railextension.

Embodiment 45

The method of any of Embodiments 36-44, wherein the first portion andthe second portion are symmetrical along a horizontal axis of the railextension.

Embodiment 46

The method of any of Embodiments 36-45, wherein joining the firstportion and the second portion comprises at least one of vibrationwelding, adhesive, and combinations including at least one of theforegoing.

Embodiment 47

The method of any of Embodiments 36-47, wherein the first portion andthe second portion are formed in the same mold cavity.

Embodiment 48

A rail extension, comprises: a base extending from an end of the railextension, wherein the base includes vehicle rail attachments configuredto attach to a vehicle rail; a front member configured for attachment toa bumper beam; a body extending from the base to the front member;wherein the body comprises reinforcing members; wherein the bodycomprises a first polymeric material; wherein the reinforcing memberscomprise a second polymeric material.

Embodiment 49

The rail extension of Embodiment 48, further comprising an outer shelllocated around at least an outer portion of the rail extension.

Embodiment 50

The rail extension of Embodiment 48 or Embodiment 49, wherein the firstpolymeric material comprises polycarbonate, polyamide, polyphenyleneether, polybutylene terephthalate, polyethylene terephthalate, andcombinations including at least one of the foregoing.

Embodiment 51

The rail extension of any of Embodiments 48-50, wherein the secondpolymeric material comprises reinforced polymeric material.

Embodiment 52

The rail extension of any of Embodiments 48-51, wherein the outer shellcomprises a metallic material, carbon fiber reinforced polymericmaterial, glass fiber reinforced polymeric material and combinationsincluding at least one of the foregoing.

Embodiment 53

The rail extension of any of Embodiments 48-52, wherein the firstportion and the second portion are symmetrical along a vertical axis ofthe rail extension.

Embodiment 54

The rail extension of any of Embodiments 48-53, wherein the firstportion and the second portion are symmetrical along a horizontal axisof the rail extension.

Embodiment 55

The rail extension of any of Embodiments 48-54, wherein joining thefirst portion and the second portion comprises at least one of vibrationwelding, adhesive, and combinations including at least one of theforegoing.

Embodiment 56

A method of making a rail extension of any of Embodiments 48-55,comprising forming the front member, body, base, and reinforcing membersthrough an additive manufacturing process.

All ranges disclosed herein are inclusive of the endpoints, and theendpoints are independently combinable with each other (e.g., ranges of“up to 25 wt. %, or, more specifically, 5 wt. % to 20 wt. %”, isinclusive of the endpoints and all intermediate values of the ranges of“5 wt. % to 25 wt. %,” etc.). “Combination” is inclusive of blends,mixtures, alloys, reaction products, and the like. Furthermore, theterms “first,” “second,” and the like, herein do not denote any order,quantity, or importance, but rather are used to denote one element fromanother. The terms “a” and “an” and “the” herein do not denote alimitation of quantity, and are to be construed to cover both thesingular and the plural, unless otherwise indicated herein or clearlycontradicted by context. The suffix “(s)” as used herein is intended toinclude both the singular and the plural of the term that it modifies,thereby including one or more of that term (e.g., the film(s) includesone or more films). Reference throughout the specification to “oneembodiment”, “another embodiment”, “an embodiment”, and so forth, meansthat a particular element (e.g., feature, structure, and/orcharacteristic) described in connection with the embodiment is includedin at least one embodiment described herein, and may or may not bepresent in other embodiments. In addition, it is to be understood thatthe described elements may be combined in any suitable manner in thevarious embodiments.

While particular embodiments have been described, alternatives,modifications, variations, improvements, and substantial equivalentsthat are or may be presently unforeseen may arise to applicants orothers skilled in the art. Accordingly, the appended claims as filed andas they may be amended are intended to embrace all such alternatives,modifications variations, improvements, and substantial equivalents.

1. A rail extension, comprising: a base extending from one end of therail extension, wherein the base includes vehicle rail attachmentsconfigured to attach to a vehicle rail; a front member configured forattachment to a bumper beam; a body extending from the base and towardthe front member, wherein the base comprises cells formed by cell wallsextending along at least a portion of a length of the body from the basetoward the front member and forming cavities therethrough; open channelsformed on each side of the body, wherein the open channels are definedby walls of adjacent cells; wherein the front member comprises aplurality of beam attachments that extend from the front member towardsthe base; and beam attachment inserts located within the beamattachments.
 2. The rail extension of claim 1, further comprising railattachment inserts located within the rail attachments.
 3. The railextension of claim 1, further comprising a plate coupled to the frontmember, wherein the plate comprises an anti-climbing member extendingtoward the base and sized to fit within a cell and an anti-clashingmember extending away from the base and configured to fit within arecess of the bumper beam.
 4. The rail extension of claim 1, wherein thecells extend an entire length of the body, or wherein at least some ofthe cells do not extend the length of the body from the base to thefront member.
 5. The rail extension of claim 1, wherein across-sectional area of a cell varies from the front member to the baseand wherein a thickness of at least a portion of the cell wall variesfrom the front member to the base.
 6. The rail extension of claim 1,wherein the rail extension comprises polybutylene terephthalate;acrylonitrile-butadiene-styrene; polycarbonate; polycarbonate/PBTblends; polycarbonate/ABS blends; copolycarbonate-polyesters;acrylic-styrene-acrylonitrile; acrylonitrile-(ethylene-polypropylenediamine modified)-styrene; phenylene ether resins; blends ofpolyphenylene ether/polyamide; polyamides; phenylene sulfide resins;polyvinyl chloride; high impact polystyrene; low/high densitypolyethylene; polypropylene; expanded polypropylene; thermoplasticolefins; and combinations including at least one of the foregoing. 7.The rail extension of claim 1, wherein cells adjacent to channels on twoopposing sides of the body have a beveled surface and wherein thebeveled surface has a chamfer angle of greater than 0 to 60°.
 8. Therail extension of claim 1, wherein the body comprises a crush initiatorand wherein the body increases in cross-sectional area in a steppedgeometry from the front member to the base.
 9. The rail extension ofclaim 1, further comprising an anti-climbing member coupled to the frontmember and extending into a cell and a tab extending from the frontmember into a channel, wherein the tab comprises a beam attachment. 10.A vehicle, comprising: a bumper beam; a vehicle rail; and the railextension of claim 1 coupled to the bumper beam and the vehicle rail.11. The vehicle of claim 10, wherein the rail extension is a polymericrail extension; wherein the polymeric rail extension further comprisesan aperture extending through the base to the front member; and aconnection member attached to the bumper beam and extending through theaperture configured to attach the rail extension to the vehicle rail.12. The rail extension system of claim 11, wherein the connection memberfurther comprises bumper beam attachments extending from the connectionmember and configured for attachment to the bumper beam and the frontmember and wherein the rail extending system further comprises a railattachment plate attached to the vehicle rail; wherein the railattachment plate comprises a rail attachment insert; and a fastenerconfigured to attach the connection member to the rail attachmentinsert.
 13. A method of forming a rail extension, comprising: molding afirst portion; molding a second portion; and joining the first portionand the second portion; wherein the first portion and the second portionare symmetrical about an axis of the rail extension; wherein the firstportion and the second portion comprise a base extending from one end ofthe rail extension having vehicle attachment configured to attach to avehicle rail; a front member configured for attachment to a bumper beam;and a body extending from the base to the front member.
 14. The methodof claim 13, wherein the first portion and the second portion comprise afirst polymeric material overmolded onto a second polymeric material.15. The method of claim 13, wherein the first portion and the secondportion comprise reinforcing members.
 16. The method of claim 15,wherein the reinforcing members comprise a different polymeric materialor the same polymeric material as the first portion and the secondportion and wherein the first polymeric material comprisespolycarbonate, polyamide, polyphenylene ether, polybutyleneterephthalate, polyethylene terephthalate, and combinations including atleast one of the foregoing and wherein the second polymeric materialcomprises a reinforced polymeric material.
 17. A rail extension,comprising: a base extending from an end of the rail extension, whereinthe base includes vehicle rail attachments configured to attach to avehicle rail; a front member configured for attachment to a bumper beam;a body extending from the base to the front member; wherein the bodycomprises reinforcing members; wherein the body comprises a firstpolymeric material; wherein the reinforcing members comprise a secondpolymeric material.
 18. The rail extension of claim 17, wherein thefirst polymeric material comprises polycarbonate, polyamide,polyphenylene ether, polybutylene terephthalate, polyethyleneterephthalate, and combinations including at least one of the foregoing.19. The rail extension of claim 17, wherein the second polymericmaterial comprises reinforced polymeric material.
 20. A method of makinga rail extension of claim 17, comprising forming the front member, body,base, and reinforcing members through an additive manufacturing process.